English
If A and B are linearly disjoint and every element of A commutes with every element of B, then B is linearly disjoint from A.
Русский
Если A и B линейно дизъюнктны и все элементы A коммутируют с элементами B, то B линейно дизъюнктна по отношению к A.
LaTeX
$$$A.LinearDisjoint B \Rightarrow B.LinearDisjoint A \quad \text{(under commuting condition).}$$$
Lean4
/-- Linear disjointness is symmetric if elements in the module commute. -/
theorem symm_of_commute (H : A.LinearDisjoint B) (hc : ∀ (a : A) (b : B), Commute a.1 b.1) : B.LinearDisjoint A :=
Submodule.LinearDisjoint.symm_of_commute H hc